Consider sterilization of the pharmaceutical product of Problem 8.27. To avoid any possibility of heating the product to an unacceptably high temperature, atmospheric steam is condensed on the exterior of the tube instead of using the resistance heater, providing a uniform surface temperature, Ts = 100°C.

(a) For the conditions of Problem 8.27 determine the required length of straight tube, Ls, that would be needed to increase the mean temperature of the pharmaceutical product from 25°C to 75°C.

(b) Consider replacing the straight tube with a coiled tube characterized by a coil diameter C = 100 mm and a coil pitch S = 25 mm. Determine the overall length of the coiled tube, LCI (i.e., the product of the tube pitch and the number of coils), necessary to increase the mean temperature of the pharmaceutical to the desired value.

(c) Calculate the pressure drop through the straight tube and through the coiled tube.

(d) Calculate the steam condensation rate.